The principal goal of this project for the coming year will be to identify proteins other than albumin which exist in fetal and newborn plasmas and bind pentobarbital. This will be accomplished by fractionation of sera of fetal and newborn pigs into component proteins and examining the isolated proteins for binding capacity with this ligand. The procedures to be used include polyethylene glycol fractionation, immunologic fractionation and starch block electrophoresis. An attempt will also be made to isolate the binding fraction by affinity chromatography using a support stabilized barbituric acid derivative. Similar studies will be conducted on human placental cord sera to determine whether or not these binding fractions exist in the human neonate as well.